The patch titled
Subject: Makefile: move stack-protector availability out of Kconfig
has been added to the -mm tree. Its filename is
makefile-move-stack-protector-availability-out-of-kconfig.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/makefile-move-stack-protector-availability-out-of-kconfig.patch
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/makefile-move-stack-protector-availability-out-of-kconfig.patch
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*** Remember to use Documentation/SubmitChecklist when testing your code ***
The -mm tree is included into linux-next and is updated
there every 3-4 working days
------------------------------------------------------
From: Kees Cook <keescook@xxxxxxxxxxxx>
Subject: Makefile: move stack-protector availability out of Kconfig
Various portions of the kernel, especially per-architecture pieces,
need to know if the compiler is building with the stack protector.
This was done in the arch/Kconfig with 'select', but this doesn't
allow a way to do auto-detected compiler support. In preparation for
creating an on-if-available default, move the logic for the definition of
CONFIG_CC_STACKPROTECTOR into the Makefile.
Link: http://lkml.kernel.org/r/1510076320-69931-3-git-send-email-keescook@xxxxxxxxxxxx
Signed-off-by: Kees Cook <keescook@xxxxxxxxxxxx>
Tested-by: Laura Abbott <labbott@xxxxxxxxxx>
Cc: Masahiro Yamada <yamada.masahiro@xxxxxxxxxxxxx>
Cc: Arnd Bergmann <arnd@xxxxxxxx>
Cc: Josh Triplett <josh@xxxxxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
Makefile | 6 +++++-
arch/Kconfig | 8 --------
arch/x86/Kconfig | 2 +-
3 files changed, 6 insertions(+), 10 deletions(-)
diff -puN arch/Kconfig~makefile-move-stack-protector-availability-out-of-kconfig arch/Kconfig
--- a/arch/Kconfig~makefile-move-stack-protector-availability-out-of-kconfig
+++ a/arch/Kconfig
@@ -524,12 +524,6 @@ config HAVE_CC_STACKPROTECTOR
- its compiler supports the -fstack-protector option
- it has implemented a stack canary (e.g. __stack_chk_guard)
-config CC_STACKPROTECTOR
- def_bool n
- help
- Set when a stack-protector mode is enabled, so that the build
- can enable kernel-side support for the GCC feature.
-
choice
prompt "Stack Protector buffer overflow detection"
depends on HAVE_CC_STACKPROTECTOR
@@ -550,7 +544,6 @@ config CC_STACKPROTECTOR_NONE
config CC_STACKPROTECTOR_REGULAR
bool "Regular"
- select CC_STACKPROTECTOR
help
Functions will have the stack-protector canary logic added if they
have an 8-byte or larger character array on the stack.
@@ -564,7 +557,6 @@ config CC_STACKPROTECTOR_REGULAR
config CC_STACKPROTECTOR_STRONG
bool "Strong"
- select CC_STACKPROTECTOR
help
Functions will have the stack-protector canary logic added in any
of the following conditions:
diff -puN arch/x86/Kconfig~makefile-move-stack-protector-availability-out-of-kconfig arch/x86/Kconfig
--- a/arch/x86/Kconfig~makefile-move-stack-protector-availability-out-of-kconfig
+++ a/arch/x86/Kconfig
@@ -319,7 +319,7 @@ config X86_64_SMP
config X86_32_LAZY_GS
def_bool y
- depends on X86_32 && !CC_STACKPROTECTOR
+ depends on X86_32 && CC_STACKPROTECTOR_NONE
config ARCH_SUPPORTS_UPROBES
def_bool y
diff -puN Makefile~makefile-move-stack-protector-availability-out-of-kconfig Makefile
--- a/Makefile~makefile-move-stack-protector-availability-out-of-kconfig
+++ a/Makefile
@@ -678,7 +678,7 @@ else
endif
endif
# Find arch-specific stack protector compiler sanity-checking script.
-ifdef CONFIG_CC_STACKPROTECTOR
+ifdef stackp-name
stackp-path := $(srctree)/scripts/gcc-$(SRCARCH)_$(BITS)-has-stack-protector.sh
stackp-check := $(wildcard $(stackp-path))
# If the wildcard test matches a test script, run it to check functionality.
@@ -687,6 +687,10 @@ ifdef CONFIG_CC_STACKPROTECTOR
stackp-broken := y
endif
endif
+ ifndef stackp-broken
+ # If the stack protector is functional, enable code that depends on it.
+ KBUILD_CPPFLAGS += -DCONFIG_CC_STACKPROTECTOR
+ endif
endif
KBUILD_CFLAGS += $(stackp-flag)
_
Patches currently in -mm which might be from keescook@xxxxxxxxxxxx are
makefile-move-stack-protector-compiler-breakage-test-earlier.patch
makefile-move-stack-protector-availability-out-of-kconfig.patch
makefile-introduce-config_cc_stackprotector_auto.patch
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